Concrete has a coefficient of linear expansion of about 8 × 10-6 /°C. If you were to build a bridge from concrete panels, you would have to leave a gap between them so that the concrete panels would have room to expand on a hot day. Suppose you leave a gap of 1.5 cm between panels, and you require that the panels must expand by only 1.3 cm when the temperature rises by 60 °C. What is the maximum length of the concrete panels?